Sulfite oxidase, immobilization

Sulfite is used in large amounts in paper production and as a reduc-tant in various chemical reactions. Fonong (1986a) immobilized sulfite oxidase (EC 1.8.3.1) covalently on a collagen membrane which was attached to a hydrogen peroxide-indicating Pt electrode. H2O2 liberated in the enzymatic reaction ... 

The application of immobilized sulfite oxidase in the Multipurpose Bioanalyzer (Provesta, USA) has been described by Smith (1987). 1.8 U of the enzyme was entrapped in a gel at the active tip of an oxygen probe. The sensor is suitable for sulfite determination in food samples down to 100 ppm and has a lifetime of 84 days. 

The simultaneous determination of sulfite and phosphate in wine was proposed by Yao et al. (1994), where a FI A system was coupled with amperometric detection. In this approach two different reactors with immobilized sulfite oxidase and co-immobilized purine nucleoside phosphorylase-xanthine oxidase were incorporated in a parallel configuration. The enzymatically generated hydrogen peroxide was selectively detected on a poly(l,2-diaminobenzene)-coated platinum electrode. Because of the different residence times at each channel, two different peaks could be obtained, the first corresponding to sulfite and the second to phosphate. Using this system, the analytes could be simultaneously analyzed with a linear range of 1 x 10 -2 x 10 M (sulfite) and 2 x 10 -5 x 10 M (phosphate) and a sample throughput of 30 Mb... 

Spricigo R, Dronov R, Lisdat F, Leimkuhler S, Scheller FW, Wollenberger U (2009) Electrocatalytic sulfite biosensor with human sulfite oxidase co-immobilized with cytochrome c in a polyelectrolyte-containing multilayer. Anal Bioanal Chem 393 225-233... 

Enzymatic electrochemical biosensors are based on immobilized enzymes, whose products can be electrochemically measured after degradation of the substrate at the surface of the biosensor. Many different types of enzymatic biosensors have been developed for environmental monitoring of pesticides, phenols, heavy metals, nitrate, formaldehyde and sulfur oxide, etc. Commonly used enzymes include but are not limited to organophosphorus hydrolase (OPH), AChE, butyrylcholi-nesterase (BChE), horseradish peroxidase (HRP), tyrosinase (phenol oxidases), nitrate reductase, nitrite reductase, formaldehyde dehydrogenase (FDH), and sulfite oxidase (SO). 

---